Multilouver roughness silencer

ABSTRACT

A muffler has a sinuous louvered partition extending longitudinally of the casing and alongside a straight-through gas flow tube to provide a series of expansion chambers that are in parallel with the gas flow through the muffler.

United States Patent Bert DuBois Brooklyn, Mich. Appl. No. 58,394

Filed July 27, 1970 Patented Oct. 19, 1971 Assignee Tenneeo lne. Racine,Wis.

Inventor MULTILOUVER ROUGHNESS SILENCER 5 Claims, 2 Drawing Figs.

US. Cl 181/48, 181/63 Int. Cl F0ln ll04,

FOln 1/ 10 Field of Search 181/48,

[5 6] References Cited UNITED STATES PATENTS 2,038,309 4/1936 Oldberg3,485,319 12/1969 Balluff FOREIGN PATENTS 822,559 9/1937 France 394,71312/ 1 965 Switzerland Primary Examiner-Robert S. Ward, Jr.Attorney-Harness, Dickey & Pierce ABSTRACT: A muffler has a sinuouslouvered partition extending longitudinally of the casing and alongsidea straightthrough gas flow tube to provide a series of expansionchambers that are in parallel with the gas flow through the muffler.

MULTILOUVER ROUGI'INESS SILENCER BRIEF SUMMARY OF THE INVENTION It isthe purpose of this invention to provide a low back pressure mufflercontaining silencing structure that substantially DESCRIPTION OF THEDRAWINGS FIG. 1 is a longitudinal cross section of a muffler, shownsomewhat schematically, embodying the invention; and FIG. 2 is a crosssection along the line 22 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION The muffler 1 has a tubularhousing 3 which is preferably of oval cross section as seen in FIG. 2.The opposite ends of the housing 3 are closed by an inlet header 5 andan outlet header 7 which are interlocked in gastight joints 9 with theends of the shell 3. The headers 5 and 7 have outwardly extendingcollars 11 and 13 which receive a straight-through gas flow tube 15 thatcan conduct gas straight through the muffler 1 from the exhaust pipe 17to the tailpipe 19.

The tube 15 is perforated, preferably in form of louvers 21 extendingover a substantial portion of its length within the housing 3 as can beseen in FIG. 1. The tube 15 is preferably located off center of theoval-shaped housing 3 as can be seen in FIG. 2. A sinuously shapedlongitudinal partition 23, which extends longitudinally of the mufflerand parallel to the tube 15, is located to one side of the tube 15 todefine a chamber 25 extending longitudinally of the shell 3 andcontaining tube 15.

The partition 23 is bent back and forth to provide a series oflongitudinally extending partition sections 27, 29, 31, and 33 whichsubdivide the rest of the space within the housing 3 into transverselyseparated longitudinal chambers 35, 37, 39, and 41. The partitionsections are interconnected by transverse sections 43, 45, and 47, whichare located on alternately located or opposite sides of the partition23, and which engage and are spotwelded to the shell 3 along withflanges 49 and 51 which extend outwardly from the two end partitionsections 27 and 33. Preferably, the partition 29 terminates a shortdistance from each header 5 and 7, as seen in FIG. 1, whereby the endchamber 41 and intermediate chambers are connected by transverse endchambers 53 and 55 to the chamber 25. Each of the partition sections 27,29, 31, and 33 is perforated, preferably by louvers 57 extending overmost of its area and along substantially all of its length and alignedwith each other and with the louve'red area in tube 15.

In operation the gas entering the muffler 3 encounters very littleresistance since it can flow straight through the pipe 15 with theresult that there is minimum horsepower loss due to back pressure.Noise-producing gas pulses can expand radially or transversely out ofthe gas tube 1 through the louvers 21 and into the chamber 25 andfurther, in series, through successive ones of the partition sections27, 29, 31, and 33 and the chambers formed by them. The multiple-serieslouver structure located in parallel with the tube 15 therefore providesa mass of means for attenuating high-frequency sounds and roughness aswell as medium frequencies. By locating the muffler 1 so that anantinode or maximum pressure point of a troublesome lower frequencyfalls in a central portion of the tube 15, attenuation of such lowerfrequencies is also accomplished.

The structure described has substantially the acoustic effect of fibrousacoustic material packed around the tube 15 or packed within themuffler. It therefore produces attenuation of the type desired bydrivers of sports vehicles, i.e., high and medium frequencies androughness are attenuated whereas some of the lower frequency, powersound remains. Additionally, the partition means 23 strengthens the ovalshell 3 to control shell noise and how].

I claim: 1. A muffler comprising a housing a oval cross section havingan inlet at one end and an outlet at the other end, a straight-throughperforated gas flow tube connecting the inlet and outlet forstraight-through flow of gas through the housing, and means providing aplurality of perforated longitudinal partitions extending substantiallyparallel to each other and to the flow tube and secured at oppositesides to the housing.

2. A muffler as set forth in claim I wherein said means comprises asinuous member having walls providing said partitions.

3. A muffler as set forth in claim 2 wherein the tube and partitions areperforated by means of louvers.

4. A muffler as set forth in claim 1 wherein said partitions terminateinwardly of the ends of the housing to provide transverse end chamberscommunicating with the gas flow tube.

5. A muffler as set forth in claim I wherein said longitudinalpartitions are secured to the housing to provide antideflection supportfor the oval cross section thereof.

1. A muffler comprising a housing a oval cross section having an inletat one end and an outlet at the other end, a straightthrough perforatedgas flow tube connecting the inlet and outlet for straight-through flowof gas through the housing, and means providing a plurality ofperforated longitudinal partitions extending substantially parallel toeach other and to the flow tube and secured at opposite sides to thehousing.
 2. A muffler as set forth in claim 1 wherein said meanscomprises a sinuous member having walls providing said partitions.
 3. Amuffler as set forth in claim 2 wherein the tube and partitions areperforated by means of louvers.
 4. A muffler as set forth in claim 1wherein said partitions terminate inwardly of the ends of the housing toprovide transverse end chambers communicating with the gas flow tube. 5.A muffler as set forth in claim 1 wherein said longitudinal partitionsare secured to the housing to provide antideflection support for theoval cross section thereof.